In a telecommunication systems and networks, transport links are interfaces between different nodes, both within the systems and networks and to other systems and networks. Said nodes may comprise different functionality entities such as Radio Base Stations, aggregation means, switching and/or routing means, e.g. as IP routers, etc., gateways, and servers. The transport links provide (Wireline) Bearer Services, which involve carrying data packets with payload. There is also a growing interest for using WIFI (technology in transport links, e.g. in back-haul systems and networks. As the multimedia applications such as Voice over IP (VoIP) and Audio/Visual (AV) streaming across the Internet emerge, IEEE 802.11 Wireless Local Area Network (WLAN) has become a prevailing broadband wireless technology of interest. Today, the IEEE 802.11 is considered a Wireless Ethernet by virtue of its best effort service provisioning based on Ethernet-like Medium Access Control (MAC) protocol. For supporting QoS in IEEE 802.11, a QoS-enabled MAC denoted IEEE 802.11e has been launched.
WIFI is a well-known technology used in the air interface between an Access Point (AP) and User Equipments (UEs). The APs and UEs operate in the un-licensed 2.4 GHz band, it has been suggested that WIFI technology transport link in a network and system supporting the RBS should operate in an un-licensed frequency band, e.g. 5 GHz. However, the use of un-licensed frequency bands raises noise disturbance problems from other users in the same frequency band by causing unpredictable interference. Since WIFI technology is not designed to support transport technology, it does not give good characteristics for distribution of packet based synchronization as the protocol standard IEEE 1588v2 PTP (Precision Time Protocol) for Ethernet and IP as well as high-precision NTP (Network Time Protocol) for IP. It is quite obvious that high amount of packet loss and delay variation in a synchronization packet stream cause performance problems in a system and network comprising different nodes and node entities, e.g. small base stations, macro base stations, require reliable and accurate coordination regarding phase synchronization and frequency synchronization.